The improvements disclosed and claimed herein have to do with the winding and the mounting oi the winding on a support within a glass envelope. While the Ayrton-Perry noninductive winding is well-known and is utilized in principle, a variation is made therein in order to avoid contact of the crossed wires at their junctype consists in the filling of the envelope with a gas having a high coeflicient of thermal conductivity and in that connection we have found that hydrogen and helium, or combinations thereof, are best fitted for that purpose. While in incandescent lamps it is not unusual to airevacuate the bulb and replace the air with a gas such as nitrogen or argon, a gas is selected in each instance that has a low coeflicient of conductivity in order to promote incandescenoe of the element. In resistors of the type here contemplated, it is desirable to avoid the change in resistance of the wire that occurs as the wire becomes more highly heated. To that end we utilize a gas such as helium with a small proportion of hydrogen therein, thus securing rapid dissipation of the heat developed and preventing such heating of the element as would greatly change its resistance.

Other features of novelty relate to the means for supporting the resistance wires and for mounting the support within the envelope. These and other features of novelty will be discussed in the following description. The invention will be more readily understood by reference to the accompanying drawings, in which:

Fig. l is a side elevation of a resistor constructed in accordance with my invention;

Fig. 2 is a view taken at right anglesto that of Fig. 1; I

Fi 3 is a Fi Fig. 4" is a side elevation 01' a modified form of winding in which a single wire is used;

Fig. 5 is a sectional view on the line H 8- I sectional view on the line 3-3 of 'tions. This is accomplished by arranging the and Herbert E. Lense,

lssignor to said Sicgel Figs. 6, 7 and 8 are plan views of the strips composed of dielectric material that are assembled as shown in Figs. 1 to in order to form the reel on which the wires are wound;

Figs. 9 and 10 are perspective views of the holding caps utilized at the ends of the reel;

Fig. 11 is an enlarged sectional detail showing the means employed for entering the resistance wires into the envelope; and,

Fig. 12 is a detail sectional view on the line l2-l2 of Fig. 2.

The device as shown in Figs. 1 and 2 includes a conventional base l5 having contact prongs IS, the resistance element being confined within a glass envelope H. In the particular form shown in Figs. 1 and 2, a second contact piece I8 is provided at the opposite end of the unit.

A feed wire l9 passes through the glass sealing element and terminates in an arm 2| to which two wires 22-23 are joined, as best shown in- Fig. 1. These wires diverge and are wound'in opposite directions on the reel in the manner respective ends.

may be telescoped or interlocked at their axes best shown in Figs. 1 and 3.

The support for the wires is of novel form and comprises three strips 24, 25, 28 composed of mice. or similar material, the strip 24 having regular notches 21 on its two side edges while the strips 25-48 have regular notches 23 on one side, but provided with alternate deep and shallow notches 29-30 on their opposite edges.

Along their axes, the strips are provided with slits, the slit 3| in strip 24 extending substantially to the middle, the slit 32 in strip 26 extending inwardly beyond the middle, while the slits 33-44 in strip 25 extend inwardly from the As so constructed, the strips to form the hexagonal figure, as shown in Fig. 3.

In order to maintain the an ular spacing as shown, we utilize the caps 35-36, the side walls of which are provided with slits 31-33 shaped to receive the wings or arms of the reel, as best shown in Fig. 12. The caps are provided with axial openings 3940 respectively to receive the longitudinal supporting members for the reel.

These supporting members comprising wires "-42, best shown in Fig. 11, have their inner end seated in glass rods 43-, shown in Figs.

2 and 3, which lie at diametrically opposite points near the center of the reel. At their opposite ends, the glass rods terminate in wires 45- oppositely bent at their point of emergence from the cap 35 to form a loop 41. A wire 43 is connected to the outer member of the loop and extends into the contact piece While the sectional means of support for the reel we provide the wire arm 54 anchored at one end in the glass part and at its other end riveted to one of the strips composing the reel.

As best shown in Fig. 11, a glass sleeve 49 guides the support wires 4I-42 and spaces the reel from the part 20. In order to interfit the mica strips with the other parts, we provide the strips 24 with end notches 50 whereby the tongue 5| may enter the sleeve, holding the strip against lateral movement and spacing apart the support wires 4l-42. The other strips 25-26 have larger notches 52-53 which pass over the outside of the sleeve 49.

The resistance wires 22-23 are, as previously stated, attached to the arm 2| and pass over.

the notched reel. The Wire 22 passes first into the notch 29' of strip 25, thence around .the reel to pass through the deep notches 29a in strip 26, thence diagonally backward to pass through the notch 29b in strip 25, thence upwardly into the While hydrogen has a slightly greater coefliclent oi thermal conductivity than helium, it is, of course, ble in the presence or oxygen and the development of a. slight leak in the envelope or connections presents the possibility of a mixture of air with the gas, resulting in an explosion when heating of the element occurs.

The described combination of gases will, however, eliminate this danger and result in highly eflicient operation. It is desirable that the gas be confined in the envelope at a pressure slightly less than atmospheric in order that when heating occurs, the resulting expansion will provide a pressure substantially equal to that of the atmosphere. r

The resistor may be used in tuning up a radio transmitter for maximum efllciency by making possible the accurate measurements 0! the radiofrequency power output of the amplifier, as well as preceding stages; it may be used also, while tuning up, to keep the signal off the air and to eliminate imnecessary interference.

We claim: w

1. In a resistance unit, having a pronged base and a sealed glass envelope, a reel within said envelope, said reel being composed of a plurality of strips of mica and resistance wires supported thereon, said strips being joined to provide radial wings, means at'the ends of the strips for mainnext regular shallow notch 21, this being re By reason of the winding the wires are at different elevations at their junctions and thus not in contact at any point through the winding.

In the modified form of winding shown in Figs. 4 and 5, we provide a single resistance wire 55 supported in the described manner and engaging a reel, the strips of which are all evenly notched at their edges. The wire in this case first engages a notch 56, then a notch 51, passing around the reel and through a notch 58; the wire is then given a reverse turn passing around the material between the notches 59-450. The wire then passes reversely around the reel to a notch 6| adjacent to the first notch 56, then diagonally forward for a repetition of the turns. In this case the wire attaches to a wire 62 at the extreme end of the reel, which wire extends axially through the assembly to emerge through the base plug in the usual manner. The construction of" the reel and its associated parts may be the same as that heretofore described.

A resistance unit such as described may be constructed to accurate specifications, will have constant radio-frequency resistance, low inductance, high Wattage dissipation and compactness. The glass envelope may be air evacuated and gas filled, it having been found that helium containing a small percentage of hydrogen constitutes an ideal gas.

taining the angular spacing of the wings, and

rod supported by the base and extending longitudinally of the reel between the wings at a point adjacent to the axis of the reel, said rods being also supported on the envelope at the end opposite the base, the last named supporting means providing an electrical connection for the said wires on said reel wound in opposite directions,

alternate wires occupying successive deep and shallow notches whereby at the point where said wires cross each other they lie in different planes.

3. In a resistance unit, having a base and a sealed glass envelope, the combination of a reel supported within the envelope, said reel coinprising a plurality of strips of dielectric material having notched edges and providing radial wings,

'the notches on' two adjacent wings being alternately deep and shallow and two resistance wires on said reel wound in opposite directions, altermeans at the end opposite the base for providing a common terminal for said resistance wires.